The association between peripheral arterial disease and risk for hip fractures in elderly men is not explained by low hip bone mineral density. Results from the MrOS Sweden study

Summary: In this prospective study in Swedish elderly men, PAD based on an ABI < 0.9 was associated with an increased risk of hip fracture, independent of age and hip BMD. However, after further adjustments for comorbidity, medications, physical function, and socioeconomic factors, the association diminished and was no longer statistically significant. Introduction: To examine if peripheral arterial disease (PAD) is associated with an increased risk for hip fracture in men independent of hip BMD. Methods: Ankle-brachial index (ABI) was assessed in the Swedish MrOS (Osteoporotic Fractures in Men) study, a prospective observational study including 3014 men aged 69–81 years at baseline. PAD was defined as ABI < 0.90. Incident fractures were assessed in computerized X-ray archives. The risk for hip fractures was calculated using Cox proportional hazard models. At baseline, BMD was assessed using DXA (Lunar Prodigy and Hologic QDR 4500) and functional measurements and blood samples were collected. Standardized questionnaires were used to collect information about medical history, falls, and medication. Results: During 10 years of follow-up, 186 men had an incident hip fracture. The hazard ratio (HR) for hip fracture in men with PAD was 1.70 (95% CI 1.14–2.54), adjusted for age and study site. Additional adjustment for total hip BMD marginally affected this association (HR 1.64; 95% CI 1.10–2.45). In a final multivariate model, the HR attenuated to a non-significant HR 1.38 (95% CI 0.91–2.11) adjusted for age, site, hip BMD, BMI, falls, smoking, eGFR, handgrip strength, walking speed, former hip fracture, antihypertensive treatment, diabetes, education, and history of cardiovascular disease. Conclusion: This study suggests that PAD is associated with an increased risk for hip fracture independently of hip BMD in elderly Swedish men. However, the high frequency of comorbidity and lower physical performance among men with PAD might partly explain this association.